Add tuna with the oil to a medium-sized mixed bowl.
Gently flake the tuna with a fork.
Stir in garlic, lemon zest, lemon juice, basil, and red onion.
Taste and season with kosher salt, black pepper, and crushed red pepper flakes.
Keep the tuna salad cold while you prepare the snack tray.
Add artichoke hearts and olives to small bowls so they do not leak onto the cutting board.
Place the small bowls of the artichokes and olives onto a large cutting board.
Add tuna salad bowl to the board and surround the bowls with crackers, cherry tomatoes, pickles, carrots, cucumbers, and watermelon radish.
Enjoy immediately.